With increase of business demand, the data rate of wireless transmission needs to be improved instantly. In the present study, the gain of cell splitting is obtained by introducing low power nodes, thereby increasing the data rate and the coverage of hot spots. However, with the densification of network nodes, the interference between the nodes has become a bottleneck of limiting network performance. Also, a great number of network nodes result in increase of power consumption, which brings a great challenge for operation costs of operators.
To avoid the mutual interference between the low power nodes, and also reduce power consumption of the low power nodes, a lot of work has done in 3GPP. For example, in Rel-10/11, the eICIC/FeICIC technology is provided to avoid the interference between the low power node and a macro base station. The mutual interference is avoided by introducing almost blank subframe (ABS) concept. However, in the technical solution, the transmission of remaining of the ABS can continue to bring interference. Furthermore, in the study of Rel-12, to avoid the interference between small cells, a concept of small cell on/off is provided, and the interference avoidance and power conservation can be realized by semi-statically turning off some small cells. However, turning off the small cells may bring influence for exiting users.
However, how to avoid the interference between small cells while high quality service for users is ensured has become a technical problem which needs to be solved instantly.